Jetted bathtubs and spas have some similarities and some differences. The similarities include the fact that they are each an opened-topped vessel of warm water. A water pump pumps water from the vessel and reinjects it into the vessel through jets to cause turbulence. Quite often there is an air pump which injects water into the pumped water stream before the jet. Many modern homes have jetted bathtubs or spas. These are equipped with mechanical timers which serve as the on-off switch. These timers are mounted on a wall on the opposite side of the room from the tub, or away from the spa to avoid shock hazard. By rotating the timer switch to the on position, the pump will start, even if there is no water in the system. If the pump is left running under these conditions, the seal bearing surfaces will overheat, causing seal damage and subsequent leakage. Thus, the user must fill enough water in the vessel to supply the needs of the pump.
Another inconvenience of the mechanical timer switch system is that when the user is in the tub, the timer will eventually go off and the pump will stop. To restart the jets, the user must get out of the tub and rotate the timer switch back to the on position and then the user gets back into the tub. The purpose of the timer is twofold. In the first case it prevents the pump from running too long unattended without water, and thus may turn off the pump sufficiently soon to prevent damage to its seal. In the other case, without such a timer the user fills sufficient water into the tub, but leaves the pump on and running unattended for hours, when the user forgets that he turned it on or when the user gets out after use of the tub and forgets to turn it off. In this case, the timer turns off the pump to prevent unnecessary pump operation.
The significant differences between the spa and the jetted bathtub are two. First, the spa is outdoors and it uses the same water for a long period of time. On the other hand, the jetted bathtub is indoors and the water is drained after each user. The fact that the jetted bathtub is drained causes it to be of smaller volume and this smaller volume permits it to be placed indoors. As far as control systems are concerned, the jetted bathtub has more need for the detection of water flow through the pump, but both the spa and jetted bathtubs have similar problems.
Therefore, there is need for a control system to control the electric motors and other electrical equipment of a spa or jetted bathtub, whereby the motors are safely controlled, but are conveniently controlled by the user. Such a system should also include safety features for this system.